{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,23]],"date-time":"2026-08-23T15:16:37Z","timestamp":1787498197439,"version":"build-2736575974"},"reference-count":46,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2022,1,18]],"date-time":"2022-01-18T00:00:00Z","timestamp":1642464000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001700","name":"Ministry of Education, Culture, Sports, Science and Technology","doi-asserted-by":"publisher","award":["16H00824"],"award-info":[{"award-number":["16H00824"]}],"id":[{"id":"10.13039\/501100001700","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>[n]Helicenes with helically twisted structures have attracted increasing interest owing to their unique properties. Therefore, it has been an important issue to develop facile synthetic methodologies which allow access to a variety of [n]helicenes. Here we report the synthesis of [7]helicenes and [7]helicene-like compounds from the thia[7]helicene as a common starting material. Desulfurative dilithiation of the thia[7]helicene and the subsequent reaction with silicon and phosphorus electrophiles afforded the silole- and phosphole-fused [7]helicene-like compounds, respectively. The cyclopentadiene-fused [7]helicene-like compound and the pyrrole-fused aza[7]helicenes were also successfully synthesized via twofold SNAr reactions of the thia[7]helicene S,S-dioxide with the carbon and nitrogen nucleophiles, respectively. The thia[7]helicene S,S-dioxide showed a slightly red-shifted absorption spectrum than the parent thia[7]helicene, which was well demonstrated by the theoretical calculations. The substituents on the silicon atom of silole-fused [7]helicene-like compounds have little impact on the longest absorption maximum. Such little effect of the substituents on absorption properties was also observed for cyclopentadiene-fused [7]helicene-like compounds and aza[7]helicenes and was well demonstrated by the theoretical calculations. The thia[7]helicene S,S-dioxide and the silole-fused [7]helicene-like compound exhibited bright blue emission, and the cyclopentadiene-fused [7]helicene-like compound and the aza[7]helicenes showed strong violet emission. Each single enantiomer of the aza[7]helicenes showed circularly-polarized luminescence with the dissymmetry factors of 4.2~4.4 \u00d7 10\u22123.<\/jats:p>","DOI":"10.3390\/molecules27030606","type":"journal-article","created":{"date-parts":[[2022,1,18]],"date-time":"2022-01-18T22:46:32Z","timestamp":1642545992000},"page":"606","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":18,"title":["Transformation of Thia[7]helicene to Aza[7]helicenes and [7]Helicene-like Compounds via Aromatic Metamorphosis"],"prefix":"10.3390","volume":"27","author":[{"given":"Keisuke","family":"Uematsu","sequence":"first","affiliation":[{"name":"Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei 184-8588, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chikara","family":"Hayasaka","sequence":"additional","affiliation":[{"name":"Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei 184-8588, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ko","family":"Takase","sequence":"additional","affiliation":[{"name":"Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei 184-8588, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Keiichi","family":"Noguchi","sequence":"additional","affiliation":[{"name":"Instrumentation Analysis Center, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei 184-8588, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4166-7074","authenticated-orcid":false,"given":"Koji","family":"Nakano","sequence":"additional","affiliation":[{"name":"Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei 184-8588, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,1,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1463","DOI":"10.1021\/cr200087r","article-title":"Helicenes: Synthesis and Applications","volume":"112","author":"Shen","year":"2012","journal-title":"Chem. 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